Driver circuits are commonly utilized to control the delivery of current from an electrical energy source to a load. A linear driver system includes a linear driver circuit which, in response to an input voltage, delivers a current to a connected load, which current is proportional to the magnitude of the input voltage. A linear driver system typically includes logic means operable to provide the input voltage to the linear driver circuit. Due to variations in components used to build linear driver circuits, some difference or error between the current actually delivered for a given input voltage and the current expected to be delivered for the given input voltage generally exists.
In certain applications such error is unacceptable. For example, in some hydraulic systems utilized in heavy machinery, precision control of a hydraulic rail pressure utilizing a linear driver system is necessary. Such precision control has previously been achieved by assembling linear driver circuits with more precise and correspondingly more expensive components in order to reduce system error. Linear driver circuits have also been tested during manufacture to assure that they fall within required specifications. In the past, even where more precise components were utilized, some linear driver circuits would not fall within required specifications and would therefore have to be reworked with different components, or even scrapped, increasing manufacturing costs.
Accordingly, the present invention is directed to overcoming one or more of the problems as set forth above.